MeiraGTx Announces Nine-Month Data from Phase 1/2 Trial of AAV-RPGR Demonstrating Significant and Sustained Vision Improvement in X-Linked Retinitis Pigmentosa (XLRP) - Seite 2

EURETINA Data Summary:

Retinal sensitivity
XLRP is characterized by progressive deterioration of the visual field. Octopus 900 full-field static perimetry and MAIA microperimetry were employed to determine change in retinal sensitivity following intervention.

Perimetry is a sensitive standard-of-care measure of retinal function that reproducibly determines retinal sensitivity both cross-sectionally and longitudinally, thereby accurately defining disease progression over time.

At the nine-month analysis (Octopus 900 static perimetry), compared to baseline:

• Six out of seven patients in the low (n=3) and intermediate (n=4) dose cohorts demonstrated improvement or stability in retinal sensitivity in the treated eye
• Improvements in treated eyes compared to baseline were sustained or further improved compared to the six-month analysis in the low and intermediate dose cohorts
• In each of the low and intermediate dose cohorts, significant improvement was observed between treated and untreated eyes in retinal sensitivity
• At the six-month timepoint, improvements in retinal sensitivity were not observed in the high dose cohort. Perimetry assessment was not carried out in the high dose cohort at the nine-month timepoint due to protocol revision implemented to align with the dose-expansion cohort assessment schedule.

Static Perimetry: Treated-Untreated Eye Difference at Nine Months (90% CI adjusted for baseline)
Mean Retinal Sensitivity (dB)
Low	0.85 (0.05, 1.63)
Intermediate	1.02 (0.78, 1.25)
Central 30° Hill-of-Vision (V30, dB-sr/y)†
Low	1.07 (0.19, 1.94)
Intermediate	1.10 (0.46, 1.74)
†Currently, at least 9 months of data and up to one year of data. Excludes one patient with panuveitis in the low dose.

Vision-guided mobility
Markedly impaired mobility in low illumination is a hallmark symptom of XLRP. As part of the study, patients completed a vision-guided mobility maze to assess their ability to navigate across a broad range of controlled light levels (1 lux = deep twilight, 4 lux = residential street lighting, 16 lux = twilight conditions, 64 lux = car park and 256 lux = office work).